Though a statement issued by the Pentagon said the attack was specifically intended to kill Soleimani and that it was ordered “at the direction of the President,” it also characterized the killing as defensive, to protect U.S. military forces abroad, and stated that Soleimani was actively developing plans “to attack American diplomats and service members in Iraq and throughout the region.” Subsequent statements by Secretary of State Mike Pompeo and President Donald Trump also characterized the killing as punishment of Soleimani for past blood on his hands.

O’Çonnell’s counter argument: Whether the killing is framed as part of an armed conflict between two states or as a police action intended to deter terrorism, it cannot be characterized as an act of self-defense because there was never a full-fledged and direct attack on the United States by Iran. The United States’s legal reason for being in Iraq is to deter the Islamic State group, not to fight against Iran, she noted, and the attacks against the U.S. by Iranian-backed militias in recent months have been intermittent and relatively limited.

”Assassination is prohibited both in peacetime law as well as on the battlefield,” she said.